LIga, thank you. I guess, by the name P. sidoides in nurseries often sold P. reniforme or its hybrids. These species are very similar in forms of gray-green leaves with velvet texture. The same manner of growth - the small shrubs; both species have tuberous roots. Form and structure of flowers too similar. Their main difference in color of flowers. P. reniforme has maroon or purple (with variations in shades), while P. sidoides - dark purple, almost black.